The present invention relates to a prism optical system using a rotationally asymmetric surface, and an image display apparatus and imaging apparatus incorporating the prism optical system.
Being composed typically of a plurality of optical surfaces, a prism optical system has been used as an optical system for viewing an image display device, wherein light emanating out of the display device enters the prism, and emits out from the prism after reflection inside, arriving at the eyeball of a viewer so that images can be viewed as enlarged virtual images. In this regard, there are prior arts, for instance, Patent Publication 1 showing a prism wherein the primary image is formed by at least three reflecting surfaces for projection onto the eyeball, and Patent Publications 1, 2 and 3 showing a hologram device located at an eyeglasses lens portion.
There has also been another prism optical system proposed in the art inclusive of an optical system comprising a cylindrical prism of parallelogram shape positioned in front of the viewer s eyeball for multi-reflections and an eyepiece lens for projection of an image onto the eyeball, and an optical system comprising a combined photoguide and eyepiece lens for projection of an image onto the eyeball (Patent Publications 4 and 5).